The present invention relates to a permanent magnetic alloy containing a rare-earth element and iron and to a method of manufacturing the same.
A Co-containing alloy such as RCo.sub.5 or R.sub.2 (CoCuFeM).sub.17 (where R is a rare-earth element such as Sm or Ce and M is a transition metal such as Ti, Zr or Hf) is known as a material for a conventional rare-earth permanent magnet. However, such a Co-containing permanent magnetic alloy has a maximum energy product (BH).sub.max of 30 MGOe or less, resulting in poor magnetic characteristics. In addition, Co is relatively expensive.
A permanent magnet which uses Fe in place of expensive Co was recently developed (J. Appl. Phys. 55(6), Mar. 15, 1984). This permanent magnetic alloy is an Nd-Fe-B alloy which has a low manufacturing cost and a maximum energy product frequently exceeding 30 MGOe. However, the alloy has magnetic characteristics which vary within a wide range, in particular, a coercive force varying from 300 Oe to 10 KOe. For this reason, the alloy cannot provide stable magnetic characteristics. Such a drawback prevents advantageous industrial application of the alloy so that an iron alloy stable predetermined magnetic characteristics with excellent reproducibility has been desired.